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By Zhibao Li, Kunming Zhai, Yan Zhang

The hydration kinetics of MgO, namely magnesia or magnesium oxide, obtained by calcination of magnesite MgCO3 or synthetic MgCO3·3H2O has been studied. Nesquehonite (MgCO3·3H2O) was prepared by the reaction of MgCl2 with Na2CO3 in a mixed-suspension mixed-product removal (MSMPR) crystallizer at 40 °C. Three magnesium oxide samples were obtained by calcination of magnesite MgCO3 or synthetic MgCO3·3H2O in muffle furnace at 900, 1100 and 1300 °C for 3 h, respectively. The hydration experiments of MgO samples were investigated at 25, 35 and 45 °C for 24 h in a stirred batch reactor. The hydration results indicate that the rate and extent of hydration of magnesia decreased remarkably with hydration temperature and increased with decreasing calcination temperature at a constant hydration temperature. The whole hydration reaction of magnesia was supposed to experience the promotive period and declining period. An empirical kinetic model ( k t p -?ln(1-??) ??) and a modification of the classical shrinking core model for diffusion control ( k t b d -?-?3 2 ????1 [1 (1 ??) ] ) have been applied to fit the experimental data of hydration in two stages, respectively. The values of kinetic parameters ( p k and d k ) were obtained by regression analysis and the activation energy of the sample at 900 °C was estimated to be 34.23 kJ/mol. The comparison between MgO from calcination of synthetic MgCO3·3H2O and a commercial MgO used in silicon steel production was carried out, indicating that special silicon steel grade MgO can be obtained by calcination of MgCO3·3H2O below 900 °C.

Jan 1, 2014

"Mineral separation by exploiting the differences in mineral or metal specific gravities (sg) has been used since antiquity. In the modern era, this is most commonly seen in the recovery of gold by the use of centrifugal concentrators and the separation of coal (low sg) from waste rock (high sg) using heavy media cyclones and jigs. Other metals, notably oxides of tin and tungsten, are successfully recovered using some combination of jigs, spirals and shaking tables. However, many conventional gravity separation systems are limited to fairly coarse (>1 mm) to medium (>100 micron) particle separations due to the limitations of the gravitational separation forces in conventional equipment.Many of the high specific gravity minerals of interest are friable (e.g. cassiterite, wolframite, etc.) and excessive fines are generated in the grinding/comminution circuits which cannot be recovered with conventional equipment and may be lost directly to the tailings stream. Recent developments in centrifugal gravity separation equipment specifically designed for fine or ultra-fine particle separation and recovery have resulted in heavy mineral particle recoveries as fine as 10-20 microns. Ongoing research work has also identified the benefit of closed-circuit, multi-stage gravity recovery circuits using some combination of centrifugal concentrators and conventional equipment (tables, spirals, flotation, etc.) which can substantially increase overall plant recovery and final concentrate grade.This paper will provide details of the evolution of non-fluidized bed gravity concentrators for high sg mineral recoveries, correlate laboratory scale development work with plant results to confirm scale-up, and show how recent flowsheet developments have contributed to significantly improved plant performance.IntroductionGravity concentration is one of the oldest and most cost effective metal and/or mineral recovery systems, ranging from the classic hand panning of alluvial gold, through to the large scale production of a wide range of metals and minerals, including gold, silver, PGMs, black sands, coal and iron oxides. Conventional gravity recovery systems, comprised of some combination of sluices, spirals, jigs and shaking tables have limited application in fine particle (i.e. <100 microns) recovery, or where there are limited differences in particle specific gravities (sg), e.g. the separation of high sg, high value metal oxides (e.g. those of tin, tantalum or tungsten), from medium sg, lower value metal sulfides such as pyrite and pyrrhotite. These unit operations tend to have limited capacity, and while double and triple turn spirals and multi-deck tables have been developed, extensive floor space is often required in order to process the tonnages incorporated in the modern mineral processing plant."

Jan 1, 2017

By Clifford Britch

"Kaiser Resources Ltd. has completed feasibility studies resulting in approval of $277,500,000 for the construction of the Greenhills Surface Coal Mine, located 35 km north of Sparwood, B.C. The mine is designed to produce 1,800,000 tonnes per year of metallurgical coal over a 20-year period by conventional truck /shovel methods.The project is in the detailed design phase, with some preparation work being carried out on the site. The major construction activities are scheduled to commence in the spring of 1981. Mine development and pre-stripping will commence in July 1981, with first coal production scheduled for mid 1983.This paper will be a general description of the project and will include a discussion of the geology, reserves, mine planning, coal handling and processing, surface facilities and related topics.IntroductionProject DefinitionThe Greenhills Project is designed to produce, by conventional truck I shovel surface mining methods, 1,800,000 clean tonnes of metallurgical coal per year for twenty years . The production/ life constraints were chosen as being meaningful for planning and evaluation purposes after appraisal of the market potential and are not limited .by economic reserves. Substantial additional strippable reserves are available which would facilitate expansion of the proposed mine life and/ or capacity. In fact , all the facilities are designed so that they can be expanded in the future to accommodate a doubling of annual coal production, and certain portions of the coal processing facilities are being installed with an annual capacity of 3,600,000 tonnes. The mine will also produce approximately 2,400,000 clean tonnes of oxidized thermal coal, mostly in the first decade."

Jan 1, 1981

By G. A. Mallory

"The South Bay Division of Selco Mining is located fifty-four miles northeast of Ear Falls Ontario on Confederation Lake. The concentrator operates five days a week and processes six hundred tons per day of copper zinc silver sulphide ore. The concentrator is comprised of crushing, grinding, differential flotation, thickening and drying circuits. The major constituents of the concentrator feed are: chalcopyrite 7%, sphalerite 20%, pyrrhotite 3%, pyrite 25 - 30% and felsitic volcanics 40 - 50%. The mine went into production in March 1971 with an anticipated three year life and is now scheduled for closure in the summer of 1981. Recent mine production has been limited to three cut and fill stopes which have widely varying ore grades, therefore mill feeds vary from 0.25 to 4% copper, 3.5 to 27% zinc, 0 to 0.4% lead and 15 to 30% iron.In mid 1977 Selco negotiated a six month rental purchase agreement with Outokumpu Instruments Canada Limited for a five stream analyser system. The Minexan 202 probes were the first Outokumpu probe type analysers installed in Canada although Outokumpus' Courier systems are well known. Installation of the system took place in April 1978 and after numerous hardware faults the six month evaluation began in August. By December it was obvious that the Minexan 202 probes with proportional detectors did not have adequate resolution to determine low copper values in either of the tailings streams. Outokumpu offered to replace the tailings analysers with a new prototype solid state detector probe the following summer. The evaluation on the five Minexan 202 probes continued until August 1979 when the new solid probe was installed. The Minexan S (solid state) probe was evaluated with the three remaining Minexan 202 probes until December 1979 when Selco elected to purchase the system."

Jan 1, 1981

By M. Ramström

"In 2002, Atlas Copco Rock Drills AB released the new rig control system (RCS) technology for all of its drill rig types. RCS opened the way for a new generation of computerized drill rigs based on modern, standard PC-computer technology. Drilling accuracy, information logging, reduction in manpower in some types, and serviceability have all taken a quantum leap forward when compared with previous generations of drill rigs. RCS is modularized and distributed by means of CAN-bus technology. This technology, which is well proven in automobile applications, forms the communication backbone of the rig. The modularity facilitates almost unlimited possibilities for the expansion and adaptation of drill rig functions."

Jan 1, 2005

By L. A. Melis, J. W. Rowson

"Cluff Mining operates the Phase II uranium mine and mill at Cluff Lake, northern Saskatchewan. During the Phase I operation, uranium tailings were generated by acid leaching of a gravity concentrate and high-grade ore for uranium recovery. The pre-treatment gravity process, as well as the high-grade nature of the ore, led to a concentration of gold in the tailings which justified the installation of a small circuit to recover the contained gold. The operating circuit consists of tailings repulping, grinding, cyanidation, carbon-in-pulp, gold recovery, and cyanide destruction by acidification, volatilization and re-neutralization. The process is described and typical operating parameters are provided. 1.0 INTRODUCTIONCluff Mining, a Saskatchewan partnership, is owned 20 percent by Saskatchewan Mining Development Corporation (SMDC) and 80 percent by Amok Ltd./Ltee. (Amok), manager and operator of the partnership.The current operation includes the Phase II uranium mining and milling facilities, located at Cluff Lake 700 km north of Saskatoon, capable of processing 300,000 tonnes of ore to produce about 4,000,000 lbs. U308 (1500 tonnes of uranium) per year.The Phase I operation was initially established to process the very high grade ""D"" uranium orebody from 1980 to 1983. The leach tailings from the operation Phase I mill operation were found to contain elevated levels of gold. These high gold values were partially due to the gravity pre-concentration step included in the uranium recovery circuit, and to the naturally high levels of gold associated with the uranium mineralization in the ""D"" orebody."

Jan 1, 1988

By R. Knapp, R. Firlotte

"Les Terrains Auriferes (LIA) Property, formerly the Malartic Goldfield (Goldfield) mine, ceased its remaining milling operations in the fall of 1994. During the early years of mining, the mill processed a non-sulfide ore with substantial carbonate mineralization.In 1977 after an extended shutdown period, ore from a nearby property, Bousquet, was processed at the mill. That ore contained larger quantities of sulfides, and unlike the old tailings, had acid generating potential.Upon closure of the L TA mill, the closure options considered for the L TA site were to cover with:1. a thin cover of 0.5 metres of borrow material (sand and gravel) to achieve basic erosion protection/stabilization; collect acidic seepage and treat with lime.2. a 2 metres of non-acid producing tailings; final surface to be vegetated.3. an engineered oxygen barrier consisting of a multi-layer cover; final surface to be vegetated.The paper presents the technological and economical methodologies that were used to select the closure alternative, describe the associated construction challenges that were faced with the implementation of the multi-layer cover concept and presents preliminary results on the cover's performance.In addition to being the first full scale demonstration of this type of multi-layer engineered oxygen barrier cover technology, this project had the advantage of using non acid producing mine tailings as part of the reclamation solution."

Jan 1, 1997

By M. Mirnezami, D. Lascelles, J. A. Finch, E. El-Ammouri

"In a previous publication, the depressant action of Mg above pH 10 on Cu-activated sphalerite was described (Lascelles et al., 2001). In the present communication, a second role, aggregation is introduced.Aggregation (i.e., the tendency of particles to cluster) is measured using settling rate and turbidity converted to an aggregation index (AI) where 0 corresponds to dispersed and 1 to aggregated. Surveys of Cu and Zn flotation stages at four concentrators showed the A1 increased significantly above pH 9. The metal ions identified in the process waters, principally Ca and Mg, were tested to determine which might be responsible. The presence of Mg was found to be the most important, 50 ppm Mg having a greater impact than 500 ppm Ca fkom pH 9 to 1 1. In one plant, poor repeatability in A1 was suspected to be related to varying Mg levels; doping with Mg significantly increased AI.In both aggregation and depression, therefore, the common feature is the impact of Mg at pH > 9. Over this pH range Mg forms a range of hydroxy species, including Mg(OH)2 precipitates. Suggested aggregation and depression mechanisms associated with these precipitates are introduced. Possible problems and opportunities arising from the findings are discussed.INTRODUCTIONProcess waters in flotation circuits contain a variety of metal ions that may introduce unwanted activation or depression. Two common metal ions are calcium and magnesium. Typical concentrations are in the range 50 ppm Mg and 500 ppm Ca (Marticorena et al., 1994, Basilio et al., 1996, Negeri et al., 1997, Nesset et al., 1998)."

Jan 1, 2002

By J. E. Nesset

"I had been requested earlier this year by MetSoc, our sister society of CIM, to contribute a chapter on technical developments in Canadian mineral processing over the past 50 years to their 50th Anniversary volume. Accepting the challenge of assembling such a chapter seemed at first a reasonably straightforward task, until one realises that the list of contributions by Canadians to mineral processing over this period has been more than just significant. It turns out to have been an extraordinarily fertile time for innovation and impact for Canadian-based technology. The list is necessarily a subjective one, however I had no trouble identifying twenty technology developments that are clearly outstanding, and there are undoubtedly others. As much as possible, I approached the individuals themselves who played key roles in each technology and asked that they tell the “story”. Without exception, all who were invited accepted eagerly and delivered more than I had hoped for. The technologies have been grouped into those that are truly Canadian innovations, such as the Knelson gravity concentrator and the McGill gas dispersion sensors in flotation, and technologies where Canadians and Canada played a very significant role in their success and implementation, such as AG/SAG grinding and ion-beam surface analysis. Also included are what may be termed technology transfer initiatives and institutions that have risen to a world class level, such as SGS Lakefield and the Canadian Mineral Processors Society of CIM. The challenge is now for the coming generation to continue this record of innovation and contribution to the industry, and that includes the (mostly) Canadian mining and metallurgical companies who have taken the longer term view and supported many of these initiatives, through their critical early years, with both financing and project sites for these ideas. Let us hope that the current trend of mining company globalization will not dampen their enthusiasm to participate. This plenary presentation will highlight many of these technologies, the individuals behind them, and their significance to the mineral processing industry."

Jan 1, 2012

By Marco A. Vera

"This paper investigates the froth function in flotation and the associated upgrading process. Flotation literature has revealed that one of the main functions of the froth phase is the cleaning of bubble-particle aggregates by rejection of entrained material. The cleaning and transport processes across the froth phase exert straining forces on these aggregates on their way up to the froth surface. These forces will impact on the recovery of bubble-particle aggregates.The grade at the top of the froth (TOF) is a parameter related to the quality of particles collected by bubbles in the pulp zone (true flotation). It has recently been demonstrated that TOF corresponds to the maximum practically attainable grade described by the recovery-grade (or enrichment ratio) curve. TOF lumps all the processes experienced by the bubble-particle aggregates before reaching the launder concentrate. This paper describes a methodology for quantifying flotation performance by means of the top of the froth sample - a touch of froth.INTRODUCTIONFroth flotation may be the most important mineral processing technique, but its theory is complex and is not completely understood even though many aspects have been studied and reviewed (Teague, 1998; Wills, 1992).Two distinct particulate systems prevail in the flotation process: a pulp phase and a froth phase (Figure 1). The pulp zone had been studied extensively; however, it is only recently that techniques to measure the froth zone performance have been developed (Contini et al., 1988; Falutsu and Dobby, 1992; Feteris et al., 1987; Seaman, 2002; Vera et al., 1999b).Flotation involves a number of mass transfer processes, occurring in the pulp phase and the froth phase. The formation of the froth and its subsequent removal are considered to be two important steps of the process. Phenomena that occur in the froth phase are known to affect flotation performance significantly (Cutting et al., 1981).Because the froth has a high free surface energy (as a result of the extensive interfacial surface between liquid and air), it appears thermodynamically unstable. The foaming is a dynamic balance, as new bubbles are added continuously from the pulp, while others disappear from the top. Under steady-state conditions, the volumes of added and subtracted air are equal (Booth, 1953)."

Jan 1, 2003

By G. Styles, K. Lye, R. Tenbergen, M. Mayhew

Requirements to produce a higher bulk concentrate grade have necessitated extensive use of on-stream analyser data and computer programming to obtain the targets set for Frood Stobie Mill as required by overall milling considerations.A brief history of milling process changes associated with the changes from a low grade (3% Ni) bulk concentrate in the sixties to a high (6 to 8.5%). Nil bulk concentrate currently will be presented.The heart of the presentation will be the computer control schemes for ""self optimisation"" of the distinct flotation sections in the plant within certain restraints to achieve targets set by the mill metallurgist.

Jan 1, 1985

By Carol E. Jones

Outline ? Reclamation is a primary mitigation. ? Understand baseline environment and land use. ? Determine reclamation goals. ? Selecting reclamation technology. ? Determine technical risk. Reclamation ? Primary Mitigation ? Through land and water disturbance, mining can have significant local and regional environmental impacts. ? Impacts can also result from associated land use changes. ? Reclamation is a primary tool that the mining industry uses to manage its environmental impacts.

May 1, 2008

By R. Grant, C. Bazin

"Brunswick Mining has investigated grinding media optimization for the purpose of improving the flotation feed and regrind product size distributions to enhance metal recoveries. This paper presents the findings of on-going testing of various sizes and shapes of grinding media. Plant observations combined with estimated breakage rates demonstrate the importance of appropriate selection of media sizes on the milling operation.IntroductionBrunswick Mining and Smelting is located near Bathurst, New Brunswick, and operates one of the world&apos;s largest lead and zinc mines. The ore mineralogy and processing flowsheet have been described elsewhere (Petruk and Schnarr, 1981; Shannon et 01., 1993). Despite the 25 years&apos; milling experience, there has been considerable disagreement as to the required grind size (Grant et 01., 1991). Since 1964, fineness of the flotation feed ranged from 60% to 80% passing 400 mesh (37 um) and averaged slightly above 71% in 1992. Results from mineralogical analysis (Petruk and Schnarr, 1981), laboratory and pilot plant experiments, as well as plant sampling (Grant et al., 1991; Hendriks and Ounpuu, 1985; Shannon et al., 1993) indicate that improved metal recoveries can be achieved by an increase in the fineness of grind, and more specifically by maximizing the amount of material in the 15 urn to 25 um range.This paper shows the results obtained so far from the evaluation of the effect of grinding media size and shape on grinding mill efficiency. The problem of finding optimum grinding media size, shape and composition has been recogrtized since the early 19405. The main criterion for the selection of media size is the size of the material to be ground (Bond, 1958). Although several relationships have been proposed to assist in the selection of grinding media size, none of them are entirely satisfactory (Wills, 1988). Other approaches using the breakage rates and process simulators were developed to help in the selection of grinding media size (Austin et al., 1976; Lo and Herbst, 1986; Concha et 01., 1992; Samskog et al., 1990; Martinovic et al., 1990). Although considerable effort was put into the analysis of grinding media size, very little information is available on the effect of grinding media shape (Norman and Decker, 1985, p. 3C-4). Norris (1952), Kelsall et al. (1973) and Herbst and Lo (1989) have shown that balls are more efficient than other shapes of grinding media including truncated cones and cubes."

Jan 1, 1994

By Tano Balbin, Valery Astakhov, Juha Timperi, Lauri Koresaar

"Online elemental analysis is the basis of optimal flotation control in mineral concentrator plants. Traditionally XRF analyzers have been used as the online analysis method. However, online XRF analyzers struggle to measure elements below calcium in atomic number (Z=20). For many processes lighter element assays would be beneficial to improve control of grade and recovery. Processes where elements below Ca are required include P, Mg and Si in phosphate concentrators, Si, Mg and Al in iron concentrators, and S and C in gold concentrators. Laser-Induced Breakdown Spectroscopy (LIBS) based elemental analysis can readily be applied to these processes. LIBS is based on generating plasma in the slurry sample by a high energy laser and analysis of the plasma by optical emission spectroscopy. Capabilities of a new Courier® 8 analyzer based in LIBS technology are demonstrated for elemental analysis starting from lithium (Z=3). Results of a plant installation in a sulfide gold concentrator provide a good agreement with the analyzer and laboratory assays.IntroductionEffective process control can be regarded as one of the fastest paying investments for a mineral processing plant. Process optimization in flotation circuits requires constant feedback of the process state. If only manual laboratory samples are available, this optimization becomes difficult due to the long delay between taking the sample and acquiring the laboratory result. If the element grades are available in online basis, the operator or automatic process control system can make corrective actions in real time.Online X-Ray Fluorescence (XRF) analyzers have been in use at concentrators for decades. The XRF analyzers can provide a fast, accurate and precise analysis from slurry streams. However, the drawback of XRF analyzers is their lack of capability to measure elements below Ca (Z=20) in atomic number. The low energy X-rays of the low atomic number elements get absorbed by water in the sample, protective window of the analyzer, or air between the sample and spectrometer."

Jan 1, 2017

By J. A. Finch

"Much progress has been made over the last several years in the ability to measure flotation cell hydrodynamic parameters in both the laboratory and plant. These techniques have allowed fundamental research to proceed to determine the effects that frother chemistry has on the main hydrodynamic parameters (gas hold up, bubble size) as well as on the amount of froth generation and water content of froth. A research program was begun that brought together a team consisting of private companies and a University with expertise in hydrodynamic characterization (McGill), flotation reagent applications (Flottec) and chemical synthesis (Sasol N.A.) with the purpose of characterizing frother chemistries with two goals in mind: Determine which frother chemistry can provide optimized cell hydrodynamics; and, create new frother chemistries with specific hydrodynamic properties.This paper describes the key steps that were taken that led to the development of new frother chemistry for use in flotation.The first step was the characterization of the major frother chemical families in a two phase system. The parameters measured were gas hold up, bubble size, froth height and water carrying rate at different concentrations and gas velocities.Analysis of the data indicated that definite patterns existed between frother chemistry and hydrodynamics and showed that frothers could be grouped into classes. More importantly, by modifying known frothers through chemical reaction it was shown that these frothers could be moved from one class to another. As a result of this better understanding of the interdependence of hydrodynamic and chemical properties, a new frother chemistry was proposed that was predicted to perform similarly to MIBC.The new frother was synthesized and hydrodynamic testing confirmed that the chemical performed similar to MIBC. Laboratory flotation tests were conducted on two different ore types that also confirmed the similar performance of the new chemical and MIBC. Subsequently, the new product was placed on a plant for a short period of time. The results showed that the product was an excellent frother but increased the flotation rate slightly more than MIBC at the same addition rate.Further research showed that the new frother chemistry was a family of products. By changing the reaction the resultant products could be made to be slightly weaker or stronger than MIBC but that this chemistry cannot provide hydrodynamic/froth characteristics similar to strong frothers like glycols and glycol ethers. Further work is planned to conduct longer plant trials to confirm the efficacy of this new frother family."

Jan 1, 2007

By J. S. Phipps, D. R. Skuse

"Aqueous slurries of fine particle size calcium carbonate are used in a diverse range of end-use products. In many cases, the end use performance is governed by the fineness of the particle size distribution. In turn, the maximum fineness of the particle size distribution is primarily determined by the efficiency of the dispersants used during the production process. Here we report the sodium polyacrylate mediated dispersion of calcite and kaolin. Firstly, we report a colloid chemical description of the dispersant behaviour and attribute the stabilisation to both steric and electrostatic mechanisms. Secondly, we describe how the understanding developed in the first part of the study can be utilised to produce more effective dispersant systems which allow the preparation of, added value, higher solids and finer particle size calcium carbonate slurry products.INTRODUCTIONConcentrated aqueous dispersions of fine, particulate kaolin and calcium carbonate are used extensively in the coating of paper. Currently more than 10 million tonnes of such dispersions are used annually in North America and Europe alone, and worldwide consumption is growing at around 3% per year.Generally, paper is coated to enhance its visual appearance. Firstly, coatings improve the optical properties of the blank sheet, i.e. its brightness (or whiteness), opacity and gloss. Secondly, they improve the physical properties of the sheet that will influence the quality of the final printed image, such as surface smoothness, porosity, and ink absorption. In order to achieve these aims economically, paper coatings must be applied at high speeds and with minimal drying costs.Kaolin and calcium carbonate pigments are the major components of most paper coating formulations. Particle size distributions are chosen to maximise the optical benefits that they confer, and to allow the production of formulations that can be easily pumped, handled and coated. Coating pigments are generally produced and transported as slurries, and so it is important to obtain dispersions with the highest possible solids content, both to minimise drying costs and the quantity of water transported. This paper examines the dispersant technology that is currently used in the industry and the mechanisms by which it functions, and illustrates ways in which this technology has developed and could be further improved in the future."

Jan 1, 2003

"The mining industry uses many types of mineral and metallurgical plants to produce saleable product from ore mined. Plant design history has left current operations with a mixture of manual operation and various forms of automated process controls. Consequently, we typically see high variability in the continuous operations together with a shortfall in the attainment of full capacity, or higher utilisation of consumables.At a level of best practice, ‘Operational Performance Excellence’ focuses on process control, using automation and control systems to deliver process optimisation. This more sophisticated delivery is a great deal more difficult than the first stage of equipment selection / installation. It includes the appropriate selection of the right instrumentation, control system, key process knowledge, individuals with a solid control engineering background / experience, and the essential backing / support of the operations management team together leading to higher value delivery. Robust solutions can be realised, considerably minimising process variation, thus leading to process optimisation. This approach results in an easier, efficient and safer process while providing considerable returns for the plant owners.How variable are your processes, and do you maintain optimised process performance with dedicated resources, modern instrumentation, ‘best practice’ control systems and performance monitoring tools? In this paper, these questions and their possible answers are discussed."

Jan 1, 2014

By P. Kolodziejczyk

Mining seismicity can be harmful both under and on the surface. ? Tremors are not totally damaging, but destructive to buildings and infrastructure, especially in highly urbanized regions, such as Upper Silesia in Poland ? Destroy the social appreciation, trust and support for mining industry ? To prevent or reduce these effects, engineers and scientists develop methods allowing prediction of ground shaking intensity near buildings and various losses that can result from it Evaluation and prediction of mining tremor?s damaging influence on buildings is usually solved with two steps: ? Estimation of local ground shaking intensity (based on known attenuation relation) and classification into one of several predefined intensity intervals ? Apply supposed relation between the shaking intensity interval and qualitatively defined damaging effects to express predicted effects This makes a mixed quantitative/qualitative procedure, difficult to analyze or optimize

Aug 1, 2013

By J. N. Hilton, D. Moffett, E. Barnes

"A recent pilot-plant program carried out at Rio Algom&apos;s Quirke uranium mine at Elliot Lake, Ontario is described. The goal of the research was the production of tailings basin effluents which were low in total radium-226. The process tested involved precipitation of radium with barium chloride and sedimentation in plastic-lined settling ponds. Adjustment of the tailings basin overflow from its normal value of pH 9.5 by addition of sulphuric acid to about pH 7.5 was found to give approximately a five-fold improvement in total radium-226 removal. A five-month demonstration test resulted in an effluent with a mean total radium-226 activity of44 pCi/L after 2.5 days settling time and 29 pCi/L after 5 days. The results from the demonstration program are used to propose a schedule of achievable total radium-226 activities where precipitation and sedimentation are employed. The maximum suggested values for 5 days nominal settling time are: 30 pCi/L in an annual mean, 45 pCi/L in a monthly mean. 60pCiIL in a weekly mean and 80 pCi/L in any single grab sample.IntroductionRadium-226 has been removed from effluents at the Elliot Lake uranium mines since the introduction of the first barium chloride treatment system in 1965. Current practice, which has changed little over the years, consists of radium-barium sulphate precipitation by the addition of a low do se of barium chloride to the clear overflow from the tailings basin(l·2l. Provision is made for the precipitate to settle in large natural or constructed ponds and lagoons. The residence time in these ponds, which depends on the site, ranges from 3 to 35 days, with varying degrees of efficiency being achieved."

Jan 1, 1981

By R. A. Ozerkevich, R. J. Voisey

"SherrGold's MacLellan V ne is located about five miles south east of Lynn Lake immediately to the east of the Keewatin River. (Figure # 1)The property is accessible by an all weather road, leading north from the provincial highway 391, which links Lynn Lake with the Town of. Leaf Rapids and the city of Thompson to the south.The MacLellan Mine (formerly the Agassiz property) was discovered in the early 1950's and optioned from Comiesa Corporation in 1979 by Sherritt. SherrGold Inc. was formed in September 1985. Sherritt then transferred the MacLellan Mine, 15 other gold prospects in the Lynn Lake area and the old Lynn Lake nickel-copper mill to SherrGold. At the same time Sherrgold entered into a management agreement with Sherritt whereby Sherritt would develop and operate the MacLellan Mine and conduct SherrGold's exploration activities.The ore body as outlined in the original feasibility study is expected to produce in excess of 300,000 ounces of gold and 450,000 ounces of silver over the next 5 years. However the deposit is open to depth and exploration is continuing on and around the main zone and the many satellite deposits.The start of construction of the MacLellan mine and mill was scheduled to phase in with the closure of the Fox copper-zinc mine located 30 miles west of Lynn Lake. The majority of the employees from the Fox Operation were either employed at the MacLellan mine or relocated to Sherritt's Ruttan Operation."

Jan 1, 1987